Document And Entity Information
Derivative Instrument Related to 2024 SSCP Notes [Member]
Represents the derivative instrument related to the 2024 SSCP Notes.
Statistical Measurement [Axis]
Note To Financial Statement Details Textual
Significant Accounting Policies
Note 3 - Cash and Cash Equivalents
Income tax expense
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 4 - Prepaid Expenses and Other Current Assets
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 5 - Property and Equipment, Net
Trading Arrangements, by Individual [Table]
Note 6 - Accrued Liabilities
Material Terms of Trading Arrangement [Text Block]
Note 7 - Leases
Note 8 - Notes Payable and Convertible Notes Payable
Note 10 - Income Taxes
Financial Instrument [Axis]
Note 11 - Benefit Plans
Note 12 - Fair Value
Comprehensive Income, Policy [Policy Text Block]
Minimum [Member]
Note 13 - Capital Stock
us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Gross unrealized losses
Note 14 - Net Loss Per Share
Gross unrealized gains
Statistical Measurement [Domain]
Note 15 - Related Party Transactions
Maximum [Member]
Note 16 - Geographic and Segment Information
Note 3 - Cash and Cash Equivalents - Available-for-sale Securities (Details)
Foreign
Note 4 - Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Details)
Retirement Plan Name [Domain]
Note 5 - Property and Equipment, Net - Schedule of Property and Equipment, Net (Details)
us-gaap_IncreaseDecreaseInAccountsReceivable
Accounts receivable
Note 5 - Property and Equipment, Net - Schedule of Depreciation Expense (Details)
United States
Note 6 - Accrued Liabilities - Schedule of Accrued Liabilities (Details)
Retirement Plan Name [Axis]
Note 7 - Leases - Maturity Analysis of Leases (Details)
Note 7 - Leases - Components of Lease Cost (Details)
Note 7 - Leases - Supplemental Cash Flow Information (Details)
Note 8 - Notes Payable and Convertible Notes Payable - Long-term Debt (Details)
Maintenance
Note 8 - Notes Payable and Convertible Notes Payable - Interest Expense (Details)
Note 8 - Notes Payable and Convertible Notes Payable - Schedule of Future Payments (Details)
Note 10 - Income Taxes - Components of Income (Loss) Before Income Taxes (Details)
Note 11 - Benefit Plans - Stock-based Compensation Expense (Details)
Business Description and Basis of Presentation [Text Block]
Note 11 - Benefit Plans - Activity Related to Outstanding Stock Options (Details)
Note 11 - Benefit Plans - Assumptions of Stock Options (Details)
Note 12 - Fair Value - Assets and Liabilities Measured on a Recurring Basis (Details)
Note 12 - Fair Value - Unobservable Inputs (Details)
Note 13 - Capital Stock - Outstanding Warrants (Details)
Note 14 - Net Loss Per Share - Computation of Basic and Diluted Net Income (Loss) Per Share (Details)
The 2022 MD Loan [Member]
Represents the 2022 MD loan.
Note 14 - Net Loss Per Share - Antidilutive Securities Excluded from Computation (Details)
Note 15 - Related Party Transactions - Revenue From 4Life Agreement (Details)
Counterparty Name [Axis]
Note 16 - Geographic and Segment Information - Profit and Loss Information by Reportable Segment (Details)
Note 16 - Geographic and Segment Information - Reconciliation of the Reportable Segments' Loss From Operations to Consolidated (Details)
Note 16 - Geographic and Segment Information - Assets by Reportable Segment (Details)
clnn_DebtConversionConversionPricePercentOf30dayTrailingVolumeweightedAverageSalePriceOfCommonStock
Debt Conversion, Conversion Price, Percent of 30-day Trailing Volume-weighted Average Sale Price of Common Stock
Represents conversion price of debt conversion into common stock as percentage of 30-day trailing volume-weighted average sale price of common stock.
Forfeited, weighted average exercise price per share (in dollars per share)
Notes To Financial Statements
Expired, weighted average exercise price per share (in dollars per share)
Notes To Financial Statements [Abstract]
Granted, weighted average exercise price per share (in dollars per share)
clnn_DebtInstrumentMonthlyInterestonlyPaymentsMaximumAmountFirstEighteenInstallments
Debt Instrument, Monthly Interest-only Payments, Maximum Amount, First Eighteen Installments
Maximum amount of monthly interest-only payments for the first eighteen installments under debt instrument.
clnn_DebtInstrumentMonthlyPrincipalAndInterestPaymentForTheNextThirtyInstallments
Debt Instrument, Monthly Principal and Interest Payment, for the Next Thirty Installments
Amount of monthly principal and interest payment for the next thirty installments under debt instrument.
The 2022 DHCD Loan [Member]
Represetns the 2022 DHCD loan.
clnn_PolicyTable
Personnel
us-gaap_LaborAndRelatedExpense
Financial Instruments [Domain]
Cash, Cash Equivalent, and Marketable Security [Text Block]
Grant Funding Related to VISIONARY-MS Phase 2 Clinical Trial [Member]
Represents Grant Funding Related to VISIONARY-MS Phase 2 Clinical Trial.
National Multiple Sclerosis Society [Member]
Represents National Multiple Sclerosis Society.
Leasehold Improvements [Member]
Counterparty Name [Domain]
us-gaap_IncreaseDecreaseInInventories
Inventory
clnn_PhantomSharesForPotentialRepayment
Phantom Shares for Potential Repayment (in shares)
The number of phantom shares for potential repayment.
clnn_GovernmentAssistanceRepaymentAdditionalPercentageOfGrantFundingTrancheOne
Government Assistance, Repayment, Additional Percentage of Grant Funding, Tranche One
Represents additional payment of the grant as a percentage of the fund, tranche one.
us-gaap_SharesOutstanding
Balances (in shares)
Balances (in shares)
clnn_GovernmentAssistanceRepaymentCumulativeSalesTrancheOne
Government Assistance, Repayment, Cumulative Sales, Tranche One
Cumulative sales amount required to repay additional grant funding, tranche one.
clnn_GovernmentAssistanceRepaymentAdditionalPercentageOfGrantFundingTrancheTwo
Government Assistance, Repayment, Additional Percentage of Grant Funding, Tranche Two
Represents additional payment of the grant as a percentage of the fund, tranche two.
clnn_GovernmentAssistanceRepaymentPercentageOfGrantFundingUponFirstCommercialProductSale
Government Assistance, Repayment, Percentage of Grant Funding Upon First Commercial Product Sale
Represents repayment amount of the grant as a percentage of grant funding upon first commercial product sale.
clnn_GovernmentAssistanceRepaymentMaximumPercentageOfGrantFundingWhenAllMilestonesAchieved
Government Assistance, Repayment, Maximum Percentage of Grant Funding When All Milestones Achieved
Represents additional payment of the grant as a percentage of the fund if all milestones are achieved.
Segment Reporting [Text Block]
clnn_GovernmentAssistanceAggregateRepaymentPercentageOfGrantFunding
Government Assistance, Aggregate Repayment, Percentage of Grant Funding
Represents aggregate amount of repayment of the grant as a percentage of the fund.
clnn_GovernmentAssistanceRepaymentPercentageOfGrantFundingUponClosing
Government Assistance, Repayment, Percentage of Grant Funding Upon Closing
Represents amount of repayment needed upon closing as a percentage of the grant funding.
clnn_GovernmentAssistanceRepaymentAmountUponClosing
Government Assistance, Repayment Amount Upon Closing
Repayment amount of the grant needed upon closing.
clnn_GovernmentAssistanceRepaymentCumulativeSalesTrancheTwo
Government Assistance, Repayment, Cumulative Sales, Tranche Two
Cumulative sales amount required to repay additional grant funding, tranche two.
clnn_GovernmentAssistanceRepaymentAdditionalPercentageOfGrantFundingTrancheThree
Government Assistance, Repayment, Additional Percentage of Grant Funding, Tranche Three
Represents additional payment of the grant as a percentage of the fund, tranche three.
clnn_GovernmentAssistanceRepaymentCumulativeSalesTrancheThree
Government Assistance, Repayment, Cumulative Sales, Tranche Three
Cumulative sales amount required to repay additional grant funding, tranche three.
Award Type [Axis]
Adjustments to reconcile net loss to net cash used in operating activities:
Plan Name [Axis]
Segment Reporting, Reconciliation of Profit (Loss) by Segment to Consolidated [Table Text Block]
us-gaap_Liabilities
TOTAL LIABILITIES
Defined Benefit Plan [Table]
Plan Name [Domain]
Segment Reporting, Reconciliation of Revenue by Segment to Consolidated [Table Text Block]
clnn_GovernmentAssistancePossibleLossPercentageOfGrantFunding
Government Assistance, Possible Loss, Percentage of Grant Funding
Represents possible loss between repayment amounts as a percentage of the grant funding.
clnn_GovernmentAssistancePossibleLossBetweenMinimumAndMaximumRepaymentAmounts
Government Assistance, Possible Loss Between Minimum and Maximum Repayment Amounts
Reflects the estimated amount of loss from minimum and maximum repayment amount.
Segment Reporting, Reconciliation of Asset by Segment to Consolidated [Table Text Block]
Accounts Payable, Accrued Liabilities, and Other Liabilities Disclosure, Current [Text Block]
us-gaap_WarrantsAndRightsOutstandingTerm
Warrants and Rights Outstanding, Term (Year)
Total stock-based compensation
Share-Based Payment Arrangement, Expense
Consolidation Items [Axis]
us-gaap_LiabilitiesAndStockholdersEquity
TOTAL LIABILITIES AND STOCKHOLDERS’ DEFICIT
Cash and Cash Equivalents [Axis]
Segment Reporting [Table]
us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets
Prepaid expenses and other current assets
us-gaap_ShareBasedCompensation
Stock-based compensation expense
Consolidation Items [Domain]
us-gaap_DebtInstrumentUnamortizedDiscountPremiumNet
Unamortized discount and debt issuance costs
ATM Facility [Member]
Represents ATM facility.
Notes Payable [Member]
Represents notes payable.
Lessee, Lease, Description [Table]
Share-Based Payment Arrangement [Text Block]
Common Stock Warrant [Member]
Represents common stock warrant.
Lease Contractual Term [Axis]
Lease Contractual Term [Domain]
Changes in operating assets and liabilities:
us-gaap_IncreaseDecreaseInAccountsPayable
Accounts payable
us-gaap_PreferredStockSharesIssued
Preferred Stock, Shares Issued (in shares)
Reconciliation of cash, cash equivalents and restricted cash to the consolidated balance sheets:
us-gaap_PreferredStockSharesOutstanding
Preferred Stock, Shares Outstanding (in shares)
us-gaap_PreferredStockSharesAuthorized
Preferred Stock, Shares Authorized (in shares)
us-gaap_RestrictedCash
Restricted cash
Restricted cash
us-gaap_PreferredStockParOrStatedValuePerShare
Preferred Stock, Par or Stated Value Per Share (in dollars per share)
us-gaap_IncreaseDecreaseInAccruedLiabilities
Accrued liabilities
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
Net increase (decrease) in cash, cash equivalents and restricted cash
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue
Balance
Balance
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents
Cash, cash equivalents and restricted cash
Effect of foreign exchange rate changes on cash and restricted cash
Cash equivalents – money market funds
Equipment
Notes payable, current portion
New Accounting Pronouncements, Policy [Policy Text Block]
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash, cash equivalents and restricted cash – beginning of period
Cash, cash equivalents and restricted cash – end of period
Concentration Risk, Credit Risk, Policy [Policy Text Block]
Antidilutive Securities, Name [Domain]
Statement [Table]
us-gaap_OperatingLeasePayments
Operating cash flows from operating leases
Business Combination, Consideration Transferred, Equity Interest, Type [Axis]
Equipment [Member]
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent
Line of Credit Facility, Lender [Domain]
us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount
Derivative liabilities
us-gaap_DerivativeLiabilities
Derivative Liability
Lender Name [Axis]
Long-Term Debt, Type [Axis]
Product and Service [Domain]
Product and Service [Axis]
Legal
us-gaap_PropertyPlantAndEquipmentUsefulLife
Property, Plant and Equipment, Useful Life (Year)
2026 (remainder)
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive
Thereafter
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue
Total minimum lease payments
Property and equipment, net
Total property and equipment, net
Property and equipment, gross
us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization
Less accumulated depreciation
us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent
Operating Lease, Weighted Average Discount Rate, Percent
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in dollars per share)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths
2027
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Forfeited, number of options (in shares)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive
2031
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExpirationsInPeriod
Expired, number of options (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)
Schedule of Maturities of Long-Term Debt [Table Text Block]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear
2026 (remainder)
Vested and exercisable, number of options (in shares)
Vested and exercisable, weighted average exercise price per share (in dollars per share)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)
Beginning balance outstanding, number of options (in shares)
Ending balance outstanding, number of options (in shares)
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree
2029
Commitments and Contingencies Disclosure [Text Block]
Nature of Expense [Axis]
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo
2028
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Beginning balance outstanding, weighted average exercise price per share (in dollars per share)
Ending balance outstanding, weighted average exercise price per share (in dollars per share)
clnn_IssuanceOfCommonStockAsPaymentOfDebt
Issuance of common stock as payment of outstanding indebtedness
The amount of adjustment for the issuance of common stock as payment of debt.
Statement [Line Items]
Private Placement [Member]
us-gaap_PaymentsForCommissions
Payments for Commissions
us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour
2030
Outstanding, intrinsic value
Outstanding, intrinsic value
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Common Stock, Shares, Issued (in shares)
Common stock, shares outstanding (in shares)
Common Stock, Shares, Outstanding (in shares)
Award Type [Domain]
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]
Risk-free interest rate
Common stock, shares authorized (in shares)
Common Stock, Shares Authorized (in shares)
Expected stock price volatility
Expected dividend yield
Schedule of Accrued Liabilities [Table Text Block]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Common stock, $0.0001 par value: 600,000,000 shares authorized; 12,778,307 and 10,849,974 shares issued and outstanding at June 30, 2026 and December 31, 2025, respectively
us-gaap_ProceedsFromIssuanceOrSaleOfEquity
Proceeds from Issuance or Sale of Equity
us-gaap_ProceedsFromIssuanceOfCommonStock
Proceeds from Issuance of Common Stock
Exercise price (in dollars per share)
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)
Issuance costs for common stock warrant liabilities
Issuance costs for common stock warrant liabilities
Amount of costs for issuance of common stock warrant liability.
us-gaap_InterestPayableCurrentAndNoncurrent
Interest Payable
Schedule of Cash and Cash Equivalents [Table Text Block]
Proceeds from issuance of common stock and warrants, net of offering costs
The cash inflow from issuance of common stock and warrants, net of issuance costs.
Accounts payable
New Avenue Warrant [Member]
Represents new avenue warrant.
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
Common stock warrant liability recorded upon public stock offering
Noncash amount of common stock warrant liability recorded upon public stock offering.
Computer Equipment [Member]
Accrued compensation and benefits
us-gaap_ComprehensiveIncomeNetOfTax
Comprehensive loss
Tranche B Warrant [Member]
Represents tranche B warrant.
Measurement Input, Probability of Fundamental Transaction [Member]
Represents probability of fundamental transaction.
Tranche A Warrant [Member]
Represents tranche A warrant.
Accrued liabilities
Total accrued liabilities
Measurement Input, Probability of Change of Control [Member]
Represents probability of change of control.
Related Party [Member]
Significant Accounting Policies [Text Block]
Measurement Input, Probability of NDA Acceptance [Member]
Represents probability of NDA acceptance.
us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount
Less amount representing interest/discounting
Non-cash lease expense
Lease obligations, net of current portion
Operating lease obligations, net of current portion
Outstanding, weighted average remaining term (Year)
Schedule of Related Party Transactions [Table Text Block]
Present value of minimum lease payments
us-gaap_OperatingLeaseLiability
Other
us-gaap_OtherAccruedLiabilitiesCurrent
Operating lease obligations, current portion
Less lease obligations, current portion
Vested, exercisable or expected to vest, weighted average remaining term (Year)
clnn_NumberOfRealEstateLeases
Number of Real Estate Leases
Represents number of real estate lease.
Thereafter
clnn_LesseeOperatingLeaseOptionToExtendPeriod
Lessee, Operating Lease, Option To Extend Period (Year)
Represents option to extend period for lessee operating lease.
Underwriting Agreement [Member]
Represents underwriting agreement.
Expected term of options (in years) (Year)
Vested and exercisable, weighted average remaining term (Year)
Capitalization, Equity [Table]
2028
2030
2029
2027
2031
Amortized cost
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]
us-gaap_LongTermDebt
Total debt principal payments
us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings
Change in fair value
Other comprehensive income (loss):
Statement of Stockholders' Equity [Abstract]
Loss Contingency Nature [Axis]
Class of Warrant or Right [Axis]
Class of Warrant or Right [Domain]
Statement of Cash Flows [Abstract]
Statutory Accounting Practices [Table]
us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent
Total other comprehensive income (loss)
Convertible notes payable, current portion
Less convertible notes payable, current portion, net of unamortized discount and debt issuance costs
Long-Term Debt, Type [Domain]
Stockholders’ deficit:
us-gaap_LossContingencyEstimateOfPossibleLoss
Loss Contingency, Estimate of Possible Loss
Equity Components [Axis]
us-gaap_IncreaseDecreaseInOperatingLeaseLiability
Operating lease obligations
us-gaap_PaymentsOfStockIssuanceCosts
Payments of Stock Issuance Costs
Share-Based Payment Arrangement [Policy Text Block]
Equity Component [Domain]
Number of shares issuable (in shares)
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)
Fair Value, Inputs, Level 2 [Member]
Fair Value, Inputs, Level 3 [Member]
Equity [Text Block]
AOCI Attributable to Parent [Member]
Fair Value, Inputs, Level 1 [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Loss Contingency, Nature [Domain]
Foreign Currency Transactions and Translations Policy [Policy Text Block]
Issuance of stock options as payment of bonus liability
Amount of decrease in additional paid in capital (APIC) resulting from direct costs associated with issuing stock as payments of bonus liability.
Payment of Bonus Liability [Member]
Payment of Bonus Liability
Payment of Outstanding Indebtedness [Member]
Payment of Outstanding Indebtedness
Property, Plant, and Equipment [Policy Text Block]
Sale of Stock [Axis]
Cost of revenue
clnn_VwapOfCommonStockForTriggerEvent
VWAP of Common Stock for Trigger Event (in dollars per share)
The VWAP of the companies common stock to trigger the trigger event.
Furniture and Fixtures [Member]
clnn_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRightsTriggerAnnouncement
Class of Warrant or Right, Exercise Price of Warrants or Rights, Trigger Announcement (in dollars per share)
The exercise price per warrant or right for the trigger announcement.
clnn_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRightsTriggerEvent
Class of Warrant or Right, Exercise Price of Warrants or Rights, Trigger Event (in dollars per share)
The exercise price of the warrants or rights for the trigger event.
Stock-based compensation expense
January 2026 Public Equity Offering [Member]
January 2026 Public Equity Offering
Measurement Input, Expected Stock Price Increase if Series A Announcement Does Not Occur [Member]
Relating to the increase in stock price if the series A announcement does not occur.
Measurement Input, Probability of Held-to-maturity [Member]
Measurement Input, Probability of Held-to-maturity
Measurement Input, Probability Series A Trigger Announcement [Member]
Relating to the series A trigger announcement.
Measurement Input, Expected Stock Price Increase if Series A Announcement Occurs [Member]
Relates to the expected stock price increase if the series A announcement occurs.
clnn_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRightsSecondTriggerEvent
Class of Warrant or Right, Exercise Price of Warrants or Rights, Second Trigger Event (in dollars per share)
Exercise price for the warrants or right for the second trigger event.
clnn_VwapOfCommonStockForSecondTriggerEvent
VWAP of Common Stock for Second Trigger Event (in dollars per share)
The VWAP of the companies common stock for the second trigger event.
Measurement Input, Probability of Held to Expiration [Member]
Measurement Input, Probability of Held to Expiration
Share-Based Payment Arrangement, Option, Activity [Table Text Block]
Deferred Employee Compensation [Member]
Deferred Employee Compensation
Convertible notes payable, net of current portion
Convertible notes payable
Amount of convertible note payable as of the balance sheet date, classified as noncurrent.
Measurement Input, Expected Stock Price Increase if Series B Announcement Does Not Occur [Member]
Related to the expected stock price increase if the series B trigger announcement does not occur.
Share-Based Payment Arrangement, Cost by Plan [Table Text Block]
Measurement Input, Probability of Series B Trigger Announcement [Member]
Related to the series B trigger announcement.
Measurement Input, Expected Stock Price Increase if Series B Announcement Occurs [Member]
Related to the expected increase in stock price if the series B announcement occurs.
clnn_DebtInstrumentConvertibleMinimumIncrementOfPrincipalForExercise
Debt Instrument, Convertible, Minimum Increment of Principal for Exercise
The minimum increment of principal the conversion feature may be exercised in for convertible debt instrument.
Fair Value Disclosures [Text Block]
Share-Based Payment Arrangement, Option [Member]
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]
Supplemental cash flow information:
Current liabilities:
us-gaap_LiabilitiesCurrent
Total current liabilities
Accounts receivable
Metals to be used in research and development
General and Administrative [Member]
Represents the general and administrative expense.
Lease, Cost [Table Text Block]
Research and Development [Member]
Represents the research and development expense.
Public and investor relations
Personnel
Lessee, Leases [Policy Text Block]
Other Commitments [Table]
Accumulated other comprehensive income
Unlikely to Vest Options [Member]
Relating to unlikely to vest options.
clnn_GovernmentAssistanceCashReceipt
Government Assistance, Cash Receipt
Represents the amount of cash receipts from government assistance during the period.
General and administrative
General and Administrative Expense
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Net loss before income taxes
Information technology
Additional paid-in capital
Debt Disclosure [Text Block]
Segment Reporting, Policy [Policy Text Block]
Use of Estimates, Policy [Policy Text Block]
Prepaid expenses and other current assets
Total prepaid expenses and other current assets
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchases of property and equipment
Issuance of common stock
Subawards [Member]
Represents the subawards for the NIH grant.
Future debt payments, net
us-gaap_DebtInstrumentCarryingAmount
Long-Term Debt, Gross
us-gaap_DebtInstrumentFairValue
Debt Instrument, Fair Value Disclosure
us-gaap_DebtInstrumentFaceAmount
Debt Instrument, Face Amount
Current assets:
Amortization of debt discount and issuance costs
Money Market Funds [Member]
us-gaap_AssetsCurrent
Total current assets
Issuance of common stock (in shares)
Stock Issued During Period, Shares, New Issues (in shares)
Prepaid clinical and CRO expenses
The amount of clinical and CRO expenses that have been prepaid
Debt Instrument, Name [Domain]
Assets that Continue to be Recognized, Transferred Financial Assets and Other Financial Assets Managed Together [Table]
Interest Rate
Debt Instrument, Interest Rate, Stated Percentage
Fair Value Measurement Inputs and Valuation Techniques [Table]
Depreciation
Depreciation expense
us-gaap_DebtInstrumentInterestRateEffectivePercentage
Debt Instrument, Interest Rate, Effective Percentage
Related and Nonrelated Parties [Axis]
us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)
us-gaap_DebtInstrumentPeriodicPaymentPrincipal
Debt Instrument, Periodic Payment, Principal
Schedule of Long-Term Debt Instruments [Table]
Debt Instrument [Axis]
us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet
Unamortized discount and debt issuance costs
Change in fair value of derivative liabilities
Unrealized Gain (Loss) on Derivatives
Change in fair value of derivative liabilities
Cash flows from operating activities:
Cash flows from investing activities:
us-gaap_NetCashProvidedByUsedInOperatingActivities
Cash Provided by (Used in) Operating Activity, Including Discontinued Operation
Net cash used in operating activities
Cash flows from financing activities:
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash used in investing activities
us-gaap_SharesIssuedPricePerShare
Shares Issued, Price Per Share (in dollars per share)
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided by financing activities
Coupon interest
Measurement Input, Probability of Dissolution [Member]
Related to the probability of dissolution.
NIH Grant Total [Member]
The total amount in the NIH grant.
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member]
Operating Segments [Member]
Accounting Policies [Abstract]
Other segment items - Research and development
us-gaap_DeferredFinanceCostsGross
Debt Issuance Costs, Gross
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block]
us-gaap_LongTermPurchaseCommitmentAmount
Long-Term Purchase Commitment, Amount
Long-Term Purchase Commitment, Category of Item Purchased [Domain]
Category of Item Purchased [Axis]
us-gaap_UnamortizedDebtIssuanceExpense
Unamortized Debt Issuance Expense
Unamortized discount and debt issuance costs
Measurement Input Type [Axis]
Income Statement [Abstract]
Cash and Cash Equivalents [Member]
Deferred grants
Measurement Input, Expected Dividend Rate [Member]
Measurement Input, Expected Term [Member]
Income Tax Contingency [Table]
us-gaap_FairValueAdjustmentOfWarrants
Change in fair value of common stock warrant liabilities
Change in fair value of common stock warrant liabilities
Measurement Input, Discount Rate [Member]
Measurement Input, Default Rate [Member]
Net loss
Net loss
Measurement Input, Price Volatility [Member]
us-gaap_GovernmentAssistanceAwardAmount
Government Assistance, Award Amount
Avenue Warrants 2023 [Member]
Represents information pertaining to the 2023 avenue warrants.
Operating expenses:
Measurement Input Type [Domain]
License Agreement [Member]
In reference to the License Agreement.
Measurement Input, Risk Free Interest Rate [Member]
Derivatives Other Than Common Stock Warrants Liabilities [Member]
Represents derivatives other than common stock warrant liabilities.
Derivative, measurement input
us-gaap_CostsAndExpenses
Total operating expenses
Income Tax Disclosure [Text Block]
Grant Funding Related to REPAIR-MS Phase 2 Clinical Trial [Member]
Relating to grant funding related to REPAIR-MS Phase 2 Clinical Trial.
clnn_NoncashInterestIncomeExpenseOnNotesPayable
Non-cash interest expense on notes payable
Represents the amount of interest income (expense) on notes payable.
Restricted Stock [Member]
Accounting Standards Update and Change in Accounting Principle [Table]
Certain Directors, Executive Officers, and Affiliated Entities [Member]
Represents information pertaining to certain directors, executive officers, and affiliated entities.
Income Tax, Policy [Policy Text Block]
Supplemental disclosure of non-cash investing and financing activities:
Related and Nonrelated Parties [Domain]
us-gaap_DeferredFinanceCostsNet
Debt Issuance Costs, Net
Related Party Transaction [Table]
Common Stock Warrant Liability [Member]
Represents the common stock warrant liability.
Clene Nanomedicine Contingent Earn-out [Member]
Represents Clene Nanomedicine contingent earn-out.
The 2024 S S C P Notes [Member]
Represents the 2024 SSCP notes.
Related Party Transactions Disclosure [Text Block]
us-gaap_RelatedPartyTransactionRate
Related Party Transaction, Rate
The 2025 S S C P Notes [Member]
Represents the 2025 SSCP notes.
clnn_DebtInstrumentConvertibleMaximumConversionAmountAmountOfPrincipalOutstanding
Debt Instrument, Convertible, Maximum Conversion Amount, Amount of Principal Outstanding
The maximum conversion amount of the outstanding principle on the convertible debt.
clnn_DebtInstrumentConvertibleAccruedInterestConversion
Debt Instrument, Convertible, Accrued Interest Conversion (in dollars per share)
The conversion rate of accrued interest on the convertible debt.
Vested, exercisable and expected to vest, number of options (in shares)
Vested, exercisable and expected to vest, weighted average exercise price per share (in dollars per share)
Vested, exercisable or expected to vest, intrinsic value
The 2025 S S C P Note [Member]
Represents the 2025 SSCP note.
Fair Value Hierarchy and NAV [Domain]
The 2024 and 2025 S S C P Notes [Member]
Represents the 2024 and 2025 SSCP notes.
Other income (expense), net:
Statement of Financial Position [Abstract]
Total other income (expense), net
us-gaap_NonoperatingIncomeExpense
Total other income (expense), net
Insurance
us-gaap_RepaymentsOfNotesPayable
Payments of notes payable
Debt Registration Fee [Member]
Represents debt registration fee.
Finance and accounting
clnn_RelatedPartyTransactionExclusiveSupplyTerm
Related Party Transaction, Exclusive Supply Term (Year)
Represents the exclusive supply term with a related party.
clnn_ManufacturingCostsNet
Manufacturing
Represents the amount of manufacturing costs net of reversals.
clnn_ClassOfWarrantOrRightRedemptionPriceUponNonexercise
Class of Warrant or Right, Redemption Price Upon Nonexercise (in dollars per share)
Represents the redemption price upon nonexercise of warrants or rights.
Document Type
clnn_DebtInstrumentCashPaymentInTheEventOfChangeInControlOrRestructuringProcessPercentageOfPrincipalOustanding
Debt Instrument, Cash Payment in the Event of Change in Control or Restructuring Process, Percentage Of Principal Outstanding
Amount of cash payment under debt instrument in the event of change in control or restructuring process as percentage of principal outstanding.
clnn_DebtInstrumentConvertibleMaximumConversionAmountPercentageOfPrincipalOustanding
Debt Instrument, Convertible, Maximum Conversion Amount, Percentage of Principal Oustanding
Maximum amount of principal that can be converted under the debt instrument as percentage of principal outstanding.
Document Information [Line Items]
Document Quarterly Report
us-gaap_LesseeOperatingLeaseTermOfContract
Lessee, Operating Lease, Term of Contract (Year)
Derivative Instrument Related to Senior Secured Convertible Promissory Notes [Member]
Represents Derivative Instrument Related to Senior Secured Convertible Promissory Notes.
us-gaap_DefinedContributionPlanCostRecognized
Defined Contribution Plan, Cost
us-gaap_LesseeOperatingLeaseRenewalTerm
Lessee, Operating Lease, Renewal Term (Year)
Reverse Recapitalization [Member]
Represents Reverse Recapitalization.
us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1
Operating Lease, Weighted Average Remaining Lease Term (Year)
Document Information [Table]
clnn_DebtInstrumentCollateralDeficiencyFeePercentage
Debt Instrument, Collateral Deficiency Fee, Percentage
Amount of collateral deficiency fee as percentage under debt instrument.
Antidilutive securities (in shares)
Antidilutive Securities [Axis]
Entity Interactive Data Current
clnn_DebtInstrumentAggregateRegistrationFeePenaltyAmountMaximumPercentageOfFaceValueOfDebt
Debt Instrument, Aggregate Registration Fee Penalty Amount, Maximum Percentage of Face Value of Debt
Maximum aggregate registration fee penalty amount allowed under debt instrument as percentage of face value of debt.
Document Transition Report
clnn_DebtInstrumentRegistrationFeePenaltyAmountPercentageOfFaceValueOfDebt
Debt Instrument, Registration Fee Penalty Amount, Percentage of Face Value of Debt
Amount of penalty as percentage of face value of debt under debt instrument.
Research and development tax credits receivable
Carrying amount due within one year of the balance sheet date (or one operating cycle, if longer) from research and development tax credits receivable.
Weighted average common shares used to compute basic and diluted net loss per share (in shares)
Convertible Notes [Policy Text Block]
Disclosure of accounting policy for convertible notes.
Derivative Instrument [Axis]
Placement Agency Agreement [Member]
Represents Placement Agency Agreement.
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]
Antidilutive Security, Excluded EPS Calculation [Table]
Net loss per share – basic and diluted (in dollars per share)
Contingent Earnout [Policy Text Block]
Disclosure for accounting policy for contingent earnout.
clnn_FairValueOfEquityIssuedExceedingOfferingProceedsAmount
Fair Value of Equity Issued Exceeding Offering Proceeds Amount
Amount of values of fair value of equity issued are over offering proceeds value.
Stock issued
Common Stock Warrants [Policy Text Block]
Disclosure of accounting policy for common stock warrants.
clnn_EquityAgentFeePercentageOfAggregateGrossProceedsOfTheOffering
Equity Agent Fee, Percentage of Aggregate Gross Proceeds of the Offering
Amount of equity issuance agent fee as percentage of aggregate gross proceeds of the offering.
Grant Funding on Conditional Grants [Member]
Represents grant funding on conditional grants.
The 2024 Pre-funded Warrants [Member]
Represents the 2024 prefunded warrants.
The 2024 Common Warrants [Member]
Represents the 2024 common warrants.
us-gaap_NotesPayableCurrent
Less notes payable, current portion, net of unamortized discount and debt issuance costs
Risk and Uncertainties [Policy Text Block]
Disclosure of accounting policy for risks and uncertainties.
Notes payable, net of current portion
Facilities
The aggregate costs of facilities.
The 2024 Pre-funded Warrants in Connection With Private Placements [Member]
Represents The 2024 Pre-funded Warrants in Connection With Private Placements.
Earnings Per Share, Policy [Policy Text Block]
The 2024 Pre-funded Warrants in Connection With Placement Agency Agreement [Member]
Represents The 2024 Pre-funded Warrants in Connection With Placement Agency Agreement.
Placement Agency Agreement and Private Placement [Member]
Represents placement agency agreement and private placement.
Office Equipment [Member]
Accretion of debt discount
Restricted Stock Awards [Member]
Represents restricted stock awards.
The 2024 S S C P Note [Member]
Represents the 2024 senior secured promissory note.
Document Fiscal Period Focus
Document Fiscal Year Focus
Restrictions on Cash and Cash Equivalents [Table]
Amendment Flag
Common Stock [Member]
Series B Warrants [Member]
Relating to Series B Warrants.
Document Period End Date
Series A Warrants [Member]
Relating to Series A Warrants.
Property, Plant, and Equipment [Text Block]
clnn_BusinessCombinationContingentEarnoutMilestoneTwoPeriod
Business Combination, Contingent Earnout, Milestone Two, Period (Year)
The period for milestone two of contingent earnout in business combination.
Long-Lived Asset, Class [Domain]
Granted, number of options (in shares)
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Grants in Period, Gross (in shares)
Variable lease costs
Legal Entity [Axis]
clnn_BusinessCombinationContingentEarnoutMilestoneOnePeriod
Business Combination, Contingent Earnout, Milestone One, Period (Year)
The period for milestone one of contingent earnout in business combination.
Operating lease costs
Business Combination, Consideration Transferred, Equity Interest, Type [Domain]
Short-term lease costs
Construction in Progress [Member]
us-gaap_LeaseCost
Total lease costs
Business Combination [Domain]
Entity File Number
Entity Tax Identification Number
Business Combination [Axis]
clnn_MinimumCashBalanceForLoanCovenant
Minimum Cash Balance For Loan Covenant
Minimum cash balance for loan covenant.
Entity [Domain]
Prepaid Expenses and Other Current Assets [Text Block]
The entire disclosure for prepaid expenses and other current assets.
Entity Central Index Key
Entity Registrant Name
us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Defined Contribution Plan, Employer Matching Contribution, Percent of Match
Foreign currency translation adjustments
Entity Current Reporting Status
Lessee, Operating and Finance Leases [Text Block]
The entire disclosure for operating and finance leases of lessee. Includes, but is not limited to, description of operating and finance lease and maturity analysis of operating and finance lease liability.
Entity Incorporation, State or Country Code
Depreciation Of Property Plant And Equipment [Table Text Block]
Tabular disclosure of depreciation of property plant and equipment.
Accrued CRO and clinical fees
Accrued CRO and clinical fees.
Current Fiscal Year End Date
Lease for Laboratory Space [Member]
Represents lease for laboratory space.
Research and development
Research and development
Research and Development Expense
Entity Filer Category
Entity Shell Company
Entity Emerging Growth Company
Capital Addition Purchase Commitments [Member]
Entity Small Business
Segment loss from operations
Segment loss from operations
Operating Income (Loss)
Loss from operations
Cash and Cash Equivalents [Domain]
Schedule of Cash Flow, Supplemental Disclosures, Leases [Table Text Block]
Tabular disclosure of supplemental cash flow information related to leases for the periods presented.
The 2019 MD Loan [Member]
Represents the 2019 MD Loan.
Cash and cash equivalents
us-gaap_Cash
Finance and Operating Lease Liability, Maturity [Table Text Block]
Tabular disclosure of undiscounted cash flows of finance and operating lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to finance and operating lease liability recognized in statement of financial position.
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Convertible Notes Payable [Member]
Department of Housing and Community Development [Member]
Represents Department of Housing and Community Development.
Regulated Operation, Regulatory Liability [Table]
The 2019 Cecil Loan [Member]
Represents the 2019 Cecil Loan.
Advance Cecil Inc. [Member]
Represents Advance Cecil Inc.
Total revenue
Revenue
Revenue:
Derivative liabilities
Total interest expense on notes payable
Entity Address, State or Province
Entity Address, City or Town
us-gaap_InterestExpenseNonoperating
Interest expense
Accumulated deficit
Retained Earnings (Accumulated Deficit)
Entity Address, Address Line One
City Area Code
Government Assistance [Policy Text Block]
Local Phone Number
Government Assistance, Type [Domain]
clnn_DebtInstrumentCovenantCashAndCertainCashEquivalentsMinimum
Debt Instrument, Covenant, Cash and Certain Cash Equivalents, Minimum
Requirement for cash and certain cash equivalents under the debt agreement.
Entity Address, Postal Zip Code
Title of 12(b) Security
Security Exchange Name
Trading Symbol
us-gaap_DebtInstrumentConvertibleConversionPrice1
Debt Instrument, Convertible, Conversion Price (in dollars per share)
Research and development tax credits and unrestricted grants
Government Assistance, Amount
Class of Stock [Axis]
First 2025 SSCPN Amendment Derivative Instrument [Member]
Relating to the first SSCPN Amendment derivative instrument.
Government Assistance, Type [Axis]
Fair value
The 2025 SSCPN Derivative Instrument [Member]
Relating to the 2025 SSCPN Derivative Instrument.
Related Party Transaction [Domain]
Entity Common Stock, Shares Outstanding
clnn_ClassOfWarrantOrRightExercisedDuringPeriod
Class of Warrant or Right, Exercised During Period (in shares)
The number of warrants or rights exercised during period.
Related Party Transaction [Axis]
Earnings Per Share [Text Block]
Other
us-gaap_OtherAssetsCurrent
Second 2024 SSCPN Amendment Derivative Instrument [Member]
Relating to Second 2024 SSCPN Amendment.
Other segment items - General and administrative
Vested and exercisable, intrinsic value
Property, Plant, and Equipment [Table]
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share (in dollars per share)
Basis of Accounting, Policy [Policy Text Block]
The 2014 Stock Plan [Member]
Represents 2014 Stock Plan.
Granted, weighted average remaining term (Year)
Weighted average remaining contractual term for option awards granted in period, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
Derivative Contract [Domain]
The 401(k) Plan [Member]
Represents the 401(k) plan.
Long-Lived Asset, Class [Axis]
Contingent Earnout Shares [Member]
Represents contingent earnout shares.
Sale of Stock [Domain]
Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block]
Embedded Derivative Financial Instruments [Member]
Total assets
us-gaap_Assets
TOTAL ASSETS
Cash and Cash Equivalents, Policy [Policy Text Block]
Loss on initial issuance of equity
Loss on initial issuance of equity
The amount of gain (loss) on issuance of equity.
Cash and cash equivalents
us-gaap_CashCashEquivalentsAndShortTermInvestments
Cash, Cash Equivalents, and Short-Term Investments
Supply Agreement [Member]
Represents supply agreement.
clnn_RelatedPartyTransactionRoyaltyFeeRateForRevenues
Related Party Transaction, Royalty Fee Rate for Revenues
Percentage of royalty fee for revenues in related party transaction.
Cash [Member]
us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Common Stock, Capital Shares Reserved for Future Issuance (in shares)
Common Stock Warrants [Member]
Represents common stock warrants.
4Life [Member]
Represents 4Life.
us-gaap_ProceedsFromLoans
Proceeds from Loans
Initial fair value of instruments issued
This value for initial fair value of instrument.
clnn_DebtInstrumentUnfundedBalance
Debt Instrument, Unfunded Balance
Amount of debt instrument that has not yet been funded.
Debt, Policy [Policy Text Block]
clnn_ResearchAndDevelopmentExpenseOther
Research
Amount of expense for research and development not specifically disclosed. Includes, but is not limited to, cost for computer software product to be sold, leased, or otherwise marketed and writeoff of research and development assets acquired in transaction other than business combination or joint venture formation or both. Excludes write-down of intangible asset acquired in business combination or from joint venture formation or both, used in research and development activity.
CNM-Au8, Amyotrophic Lateral Sclerosis [Member]
Related to product costs.
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Grant revenue as a reduction of research and development expense
The amount of grant revenue, net of a reduction of research and development expense.
CNM-Au8, Regulatory Activities [Member]
Related to product costs.
CNM-Au8, Multiple Sclerosis [Member]
Related to product costs.
Interest income
Cash paid for interest expense
General, Preclinical, Nonclinical [Member]
Related to services.
Schedule of Long-Term Debt Instruments [Table Text Block]
us-gaap_InventoryFinishedGoods
Inventory, Finished Goods, Gross
Interim Period, Costs Not Allocable [Domain]
Product [Member]
Royalty [Member]
Inventory
Grants receivable
us-gaap_InventoryRawMaterials
Inventory, Raw Materials, Gross
us-gaap_StockholdersEquity
TOTAL STOCKHOLDERS’ DEFICIT
Balances
Balances
Accrued and unpaid interest
Accrued and unpaid interest.
The 2019 Maryland DHCD [Member]
Represents the 2019 Maryland DHCD
The 2022 Maryland DHCD [Member]
Represents the 2022 Maryland DHCD
Operating lease right-of-use assets
Schedule of Interest Expense on Debt Instruments [Table Text Block]
Tabular disclosure of the interest expense for debt instruments.
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
Property, Plant, and Equipment [Table Text Block]
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
Inventory, Policy [Policy Text Block]
Commitments and contingencies (Note 9)